System and method for storing thermal energy as auxiliary power in a vehicle

ABSTRACT

There is provided a controller for a heat capture and storage system configured to capture and store energy from heat expelled in engine exhaust. The controller includes a plurality of inputs, a plurality of outputs, and at least one processor coupled to a memory for storing within the memory instructions executable by the at least one processor. The controller is configured by execution of the instructions stored in the memory to: receive signals at one or more of the plurality of inputs, the signals representing at least one operating parameter of the heat capture and storage system; and based on at least one operating parameter, generate signals at one or more of the plurality of outputs for controlling at least one component of the heat capture and storage system to capture and store the energy from the heat expelled in the engine exhaust.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/395,049, which is the National Stage of International Application No.PCT/CA2011/000315, filed Mar. 30, 2011, and claims the benefit of U.S.Provisional Patent Application No. 61/319,923, filed Apr. 1, 2010.

TECHNICAL FIELD

The present disclosure relates generally to energy storage, and moreparticularly to a system and method for capturing and storing thermalenergy as a source of auxiliary power in a vehicle.

BACKGROUND

Conventional vehicles that use internal combustion engines, such astransport trucks, either require heat from a running engine to power aheating system of the vehicle to supply heat during the winter orrequire mechanical energy generated by a running engine to turn acompressor in order to power an air-conditioning system in order tosupply cooling during the summer. Truck drivers often leave theirengines running while the truck is parked for extended periods of timein order to supply this heating or cooling while taking a break orsleeping overnight. Since trucks typically have diesel engines, thisprolonged idling results in significant amounts of pollutants beingreleased into the atmosphere. Additionally, many jurisdictions are nowimplementing anti-idling legislation, which prohibits trucks from beingleft to idle and leaves the drivers with few options for heating orcooling while taking a break inside the cab.

It would be desirable to have a system and method for capturing andstoring thermal energy as auxiliary power in a vehicle that addresses atleast some of the shortcomings of the conventional systems.

SUMMARY

One aspect of the present disclosure provides a system for capturingenergy from heat expelled in an exhaust of an engine of a motor vehicleand storing the captured energy. The system comprises a generator, acondenser, an evaporator, and an absorber. The generator captures heatfrom the exhaust of the engine and may be configured for circulating afirst solution having a solute that is vaporizable by heat captured bythe generator. The condenser may be coupled to the generator forreceiving vaporized solute and condensing the vaporized solute to aliquid. The evaporator may be coupled to the condenser and have anorifice between the condenser and the evaporator, the evaporator havinga first fluid passage for circulating the solute and a second fluidpassage for circulating a second solution. The first and second fluidpassages may be configured such that solute running through the firstfluid passage is vaporizable by heat absorbed from the second solutionrunning through the second fluid passage, thereby cooling the secondsolution. The absorber may be coupled to the evaporator and thegenerator. The absorber may be configured to return the solute tosolution by mixing the solute with a solvent of the first solutionsupplied by the generator, and for returning the first solution to thegenerator to complete a cycle of the system.

Another aspect of the present disclosure provides a method for operatingin cold storage mode a system for capturing energy from heat expelled inan exhaust of an engine of a motor vehicle and storing the capturedenergy. The method comprises absorbing heat from the engine exhaust intoa solution and vaporizing a solute of the solution, leaving behind thesolvent of the solution; cooling and condensing the solute back into aliquid; injecting the liquid solute into an evaporator, allowing thesolute to absorb thermal energy, thereby cooling a second solutionflowing through the evaporator; and further absorbing the solute backinto the solvent to reconstitute the solution for further use in theabsorbing step.

Another aspect of the present disclosure provides a method for operatingin heat storage mode a system for capturing energy from heat expelled inan exhaust of an engine of a motor vehicle and storing the capturedenergy. The method comprises absorbing heat from the engine exhaust intoa solution and vaporizing a solute of the solution, leaving behind asolvent of the solution; circulating the solute through an evaporator toenable the solute to dissipate thermal energy, thereby heating a secondsolution flowing through the evaporator; and absorbing the solute backinto the solvent and reconstituting the solution for further use in theabsorbing step.

Another aspect of the present disclosure provides a controller forcontrolling a system for capturing energy from heat expelled in anexhaust of an engine of a vehicle and storing the captured energy. Thecontroller may have at least one processor coupled to a memory forstoring within the memory instructions executable by the at least oneprocessor and a plurality of inputs and a plurality of outputs. Thecontroller may be configured to execute instructions stored in thememory and thereby receive signals at one or more of the inputs andgenerate signals at one or more of the outputs for controllingcomponents of the system to capture energy from the heat expelled in theexhaust of the engine of the vehicle and store the captured energy.

Another aspect of the present disclosure provides a heat exchanger foruse in a system for capturing energy from heat expelled in an exhaust ofan engine of a vehicle and storing the captured energy. The heatexchanger may have an outer conduit and an inner conduit. The heatexchanger captures heat from the exhaust of the engine travellingthrough the inner conduit and transfers the heat to a solutioncirculating through the outer conduit, a solute of the solution beingvaporized as heat is absorbed by the solution.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the drawings, which show by way ofexample, embodiments of the present disclosure, and in which:

FIG. 1 shows in block diagram form a thermal auxiliary power unitaccording to one aspect of the present description;

FIG. 2a shows in block diagram form a thermal auxiliary power unitoperating in a cold storage mode according to one aspect of the presentdescription;

FIG. 2b shows in flow chart form the process of a thermal auxiliarypower unit operating in a cold storage mode according to one aspect ofthe present description;

FIG. 3a shows in block diagram form a thermal auxiliary power unitoperating in a heat storage mode according to one aspect of the presentdescription;

FIG. 3b shows in flow chart form the process of a thermal auxiliarypower unit operating in a heat storage mode according to one aspect ofthe present description;

FIG. 4 shows in block diagram form a process executed by the controllerof the thermal auxiliary power unit according to one aspect of thepresent description; and

FIG. 5 shows a front view and a related sectional view of a generatorfor use with a thermal auxiliary power unit according to one aspect ofthe present description.

DETAILED DESCRIPTION

Thermal auxiliary power unit systems are described that store andrelease thermal energy in a controlled manner to enable a vehicle suchas a truck to continue to provide heating and cooling to the passengercompartment and/or to other systems within the vehicle when the mainengine is not running. Such systems may thereby reduce fuel consumption,emissions, and make it easier for drivers to comply with existing and/orupcoming anti-idling legislation. During the winter months, heat may becaptured from the engine's exhaust and/or engine cooling system and maybe stored in an insulated tank for later use. During the summer months,the heat from the vehicle exhaust system may be used to drive anabsorption refrigeration unit that cools a liquid and/or creates ice,which are stored. Some aspects of the functioning of the systems may besimilar to a combined cycle used in power plants but are suitablymodified and applied to a motor vehicle. The ice may be melted at alater time giving up its latent heat to provide a source of cooling. Inneither case is any significant additional fuel used to create theheating or cooling storage, thus reducing fuel cost for the operator whowishes to have heating or cooling available at a time that wouldnormally require leaving an engine idling while the vehicle is not beingdriven. The system may therefore make use of waste heat expelled by aninternal combustion engine by capturing the waste heat in a bottomingcycle and storing it in an absorption cycle.

The term bottoming cycle is used herein to refer to the process ofcapturing energy from exhaust heat and the term absorption cycle is usedherein to describe a style of refrigeration, which is a thermal processand not a mechanical process. For example, an absorption refrigerator isa refrigerator that uses a heat source to provide the energy needed todrive a cooling system.

Systems according to the invention may include an insulated storagevessel capable of storing up to, for example, 10 kWh of thermal energy,an absorption refrigeration unit, a battery to store sufficientelectricity for pumping, air circulation and control purposes, and heatexchangers to acquire and dispense the thermal energy through anabsorption cycle under the control of an energy management controller.One form of such systems may include a photo voltaic array thatgenerates electricity during daylight hours for storage in the battery.Another form of such systems may simply utilize a high outputmechanically-coupled alternator which charges the battery during vehicleuse.

Systems in accordance with the invention may provide an advantage overconventional truck heating, ventilating, and air-conditioning (HVAC)systems that use some fuel during driving to power a cooling or heatingsystem and that also use fuel in a direct fire heater during periodswhen the main engine is shut off. Other systems use a small auxiliaryengine and present problems with noise and vibration, maintenance, andalso use fuel and create additional emissions. Systems in accordancewith the invention may also provide a life cycle cost that uses andstores thermal energy directly with little or no operational penalty tovehicle operation. Such systems may use little or no fuel and, in someembodiments, may even reduce fuel consumption while driving. In longhaul trucks, the system may pay for itself in as little as two years dueto reduced fuel consumption from reduced idling. The system itself maybe emission free and silent or nearly silent in operation.

Referring now to FIG. 1, a block diagram is shown illustrating a thermalauxiliary power unit or system 100 according to one aspect of thepresent description. The system 100 generally includes an exhaustdiverter valve 102, a generator 104, a valve 106, a condenser 108, anevaporator pre-cooler or heat exchanger 110, a spray orifice 112, anevaporator 114, an absorber 116, an absorber pre-cooler or heatexchanger 118, a thermal storage tank 120, a thermal tank input coil andcircuit 122, a thermal tank output coil and circuit 126, a controller128, and a valve 130.

The exhaust diverter valve 102 may be coupled to an exhaust pipe of avehicle and the generator 104 and the valve 102 may ensure the thermalenergy from the engine exhaust is appropriate for the system 100 byregulating the flow of exhaust to the generator 104. In FIG. 1, theexhaust arriving from the engine to the system 100 is indicated by arrow103 and the exhaust leaving the system 100 after passing through thegenerator 104 is indicated by arrow 105. A bypass path controllable bythe valve 102 is indicated by arrow 107. In one example, the valve 102may be a 3-way, 2-position type valve and may be able to completelydivert the exhaust to or away from the generator 104 or blend betweenthe generator 104 and bypass path 107 to achieve the proper heat loadpassing through the generator 104. Optionally, the valve 102 may beomitted, but this may compromise performance on different driving cycles

The generator 104 may include a heat exchanger that receives the hotexhaust from the engine and captures heat expelled in the exhaust fromthe engine of the vehicle and transfers that energy to a solution (e.g.,water/ammonia (H₂0/NH₃)) that circulates through the generator 104. Thesolution may be heated to a point where the solute (e.g., the ammonia)boils out of the water sending the ammonia at a high pressure andtemperature out through a line to the next component in the system(e.g., either the condenser 108 in cooling mode or the evaporator 114 inheating mode). In one example, the heat exchanger component of thegenerator 104 may be the liquid to air type and may capture the heatfrom the exhaust of the vehicle engine. However, a liquid to liquid heatexchanger may also perform the same task and recover the thermal energyfrom other heat sources of the engine such as the cooling circuit of theengine. While the generator 104 is referred to throughout as agenerator, the term heat exchanger is equally applicable and thegenerator 104 may accurately be referred to as a heat exchanger. Thegenerator 104 is described in more detail below in connection with FIG.5.

The valve 106 may provide the system 100 with the ability to switchbetween heating and cooling mode by changing the fluid flow path throughthe system 100. For example, the valve 106 may be of the 3-way2-position type and may direct the flow of ammonia through the condenser108 prior to the spray orifice 112 and evaporator 114 and the system 100may function using an absorption cycle when cooling is desired. Ifheating is desired, the valve 106 may be configured to direct the flowof ammonia through a secondary circuit bypassing the condenser 108 andthe spray orifice 112, which eliminates the cooling portion of thesystem 100 and sends hot ammonia directly to the evaporator 114. Theheating and cooling modes of the system 100 will be described in greaterdetail below in connections with FIGS. 2 and 3.

The condenser 108 may include a heat exchanger that condenses the hotammonia gas back into a liquid while still under high pressure bycooling the ammonia below its boiling point while the system 100 isoperating in cooling mode. In one embodiment, the heat exchanger portionof the condenser 108 may be of the liquid to air type and may removethermal energy from the ammonia and releases it to the surroundingenvironment. It is also possible to implement the condenser 108 as theliquid to liquid type and discard the excess thermal energy elsewhere toa liquid, however this could lower the coefficient of performance of thecondenser 108. The condenser 108 may optionally have a fan (not shown)configured to pass air through the condenser 108 thereby increasing theefficiency of the condenser 108.

The evaporator pre-cooler 110 may include a heat exchanger and aims toincrease the coefficient of performance of the system 100, thereforeallowing other components to operate more efficiently. In oneembodiment, the heat exchanger portion of the evaporator pre-cooler 110is of the liquid to liquid type and transfers thermal energy between afluid passage going from the condenser 108 to the evaporator 114 andfrom a fluid passage going between the evaporator 114 and the absorber116. In one example, the fluid passages may be implemented using fluidcoils within the exchanger portion of the evaporator pre-cooler 110. Itis also possible to omit the evaporator pre-cooler 110 from the system100, but performance may be reduced.

The spray orifice 112 may include a restriction placed in the flowpassage in the cooling circuit. As the ammonia leaves the evaporatorpre-cooler 110 before the ammonia arrives at the evaporator 114, theorifice 112 causes the high pressure ammonia to be sprayed into therelatively low pressure cavity of the evaporator 114, resulting in theammonia being vaporized. The loss in pressure of the ammonia also causesa temperature drop of the ammonia.

The evaporator 114 includes a heat exchanger for transferring thermalenergy between the absorption system containing the ammonia and acircuit that transfers that thermal energy to the thermal storage tank120. In one embodiment, the heat exchanger portion of the evaporator 114is of the gas to liquid type with the ammonia flowing through a firstfluid passage (e.g., a fluid coil) of the evaporator 114 and solution(e.g., glycol/water) flowing through a second fluid passage (e.g., afluid coil) of the evaporator 114.

The absorber 116 includes a heat exchanger that allows the ammoniasolute to dissolve back into the water solvent by cooling both fluids toa temperature where such can occur. The absorber 116 may include a spraybar at its lower end. The ammonia is fed through the spray bar and sinceammonia is lighter than water, the ammonia bubbles through the water tothe top and is largely absorbed in the water. In one embodiment, theheat exchanger portion of the absorber 116 is of the liquid to air type.It is also possible to use a liquid to liquid type heat exchanger in theabsorber 116 at a lower overall system performance.

The absorber pre-cooler 118 may include a heat exchanger for increasingthe coefficient of performance of the system 100 and therefore allowingother components to operate more efficiently. In one embodiment, theheat exchanger portion of the absorber pre-cooler 118 is of the liquidto liquid type and transfers thermal energy between the ammonia/waterfluid passage connected between the absorber 116 and the generator 104and the return water fluid passage going back from the generator 102 tothe absorber 116; however it may be possible to create a system thatwould operate without the pre-cooler 118 be it at a lower coefficient ofperformance.

The thermal storage tank 120 may be, for example, a sealed storage tankthat houses and insulates thermal storage fluid and the thermal energythe fluid stores until that energy is needed for transfer elsewhere at alater time. In one example, the thermal storage fluid may be awater/glycol blend. The thermal storage tank 120 may include an inputfluid passage 122 (e.g., a fluid coil and circuit) and an output fluidpassage 124 (e.g., a fluid coil and circuit).

The input fluid passage 122 may form part of a heat exchanger and mayhave a corresponding fluid circuit and pump for transferring thermalenergy from the evaporator 114 to the thermal storage tank 120, or viceversa. In one example, the heat exchanger portion of the input fluidpassage 122 may be of the liquid to liquid type with, for example, aglycol/water blend used for the fluid in the fluid passage 122 flowingback and forth from the evaporator 114 to the thermal storage tank 120.The thermal storage tank 120 may have fluid present within the thermalstorage tank 120 in which the input fluid passage 122 is submerged. Inone example, the fluids of the fluid passage 122 and the thermal storagetank 120 are of different concentrations to achieve different effects.However, any glycol concentration in the water may be used to meet thedesign criteria of a particular application.

The thermal tank output fluid passage 124 may form part of the heatexchanger and the fluid passage 124 may be driven by a pump and may beresponsible for transferring thermal energy from the thermal storagetank 120 to the HVAC 126 unit of a vehicle. In one example, the heatexchanger portion of the thermal tank having output fluid passage 124and input fluid passage 122 may be of the liquid to liquid type with,for example, a glycol/water blend being both the fluid in the fluidpassage 124 and the thermal storage fluid present within the thermaltank 120 in which the thermal tank fluid passage 124 is submerged. Inone example, the fluids of the tank output fluid passage 124 and thethermal storage tank 120 are of different concentrations to achievedifferent effects. However, any glycol concentration in the water may beused to meet the design criteria of a particular application.

The valve 130 may be, in one example, a 3-way 3-position dual circuittype valve and may direct the flow of the solution (e.g., glycol/water)between the vehicle's HVAC 126, the vehicle's engine, and the thermalstorage tank 120. For example, if the solution in the thermal storagetank 120 is hot because the vehicle is currently being operated in acold environment such as during the winter, the valve 130 may controlthree possible operating modes. First, the valve 130 may be closed,connecting the engine to the HVAC unit 126, for example when the vehicleis moving and the heat source from the thermal storage tank is currentlynot needed while the system 100 is heating the solution in the thermalstorage tank 120 for later use. Second, the valve may be in a first openposition allowing the solution to pass from the thermal storage tank 120to the HVAC unit 126, thereby allowing the HVAC 126 to use the storedheat such as when the vehicle is parked with the engine off and a userof the system 100 desires the cabin of the vehicle to be heated. Third,the valve may be in a second open position directing the flow ofsolution to the vehicle engine. This may be useful during a cold startof the engine during cold conditions, allowing the user of the system100 to pre-heat the engine before starting the engine, thereby reducingengine wear and emissions emitted by the engine during a cold start andallowing the user to immediately use the vehicle heating system once theengine is started.

The system 100 further includes a controller 128 programmed withsuitable code for controlling the overall operation of the system 100.The controller 128 generally includes a processor coupled to a memoryfor storing and/or executing program code stored in the memory and anumber of inputs and outputs for communicating with various parts of thesystem 100. While interconnections between the components of the system100 and the controller 128 are shown in FIG. 1 in limited detail,outputs of the controller 128 may be electrically connected to any partof the system 100 controlled by the controller 128 and inputs of thecontroller 128 are electrically connected to any suitable or desiredtransducers, feedback loops, or other components of the system 100responsible for supplying input signals to the controller 128.

Pumps may also be used in the system 100 where gases or fluids need helpflowing in a particular direction, for example where pressure gradientsdo not automatically cause fluid flow to occur in a desired direction.Pumps may be suitably implemented anywhere, according to the designcriteria of a particular application. As an example, pump 128 a is shownaiding the flow of the water/glycol blend in the output fluid passage124, pump 128 b is shown aiding the flow of the water/glycol blend inthe input fluid passage 122, and pump 128 c is shown aiding the flow ofthe water/ammonia blend from the absorber 116 towards the higherpressure portion of the system 100 where the absorber pre-cooler 118 andgenerator 104 reside.

The system 100 may also have a battery (not shown) to store sufficientelectricity for pumping, air circulation (e.g., fans) and/or controlpurposes. Optionally, the system 100 may have a photovoltaic array thatgenerates electricity during daylight hours for storage in the battery.

Referring now to FIGS. 2a and 2b , collectively referred to as FIG. 2,FIG. 2a shows in block diagram form a thermal auxiliary power unit orsystem 100 operating in a cold storage mode according to one aspect ofthe present description. In FIG. 2a , the line from the valve 106 to theevaporator 114 is greyed out illustrating that this path is not usedwhen the system 100 operates in cold storage mode. FIG. 2b shows in flowchart form the process 200 of a thermal auxiliary power unit operatingin a cold storage mode according to one aspect of the presentdescription. At a first block 202, exhaust from an engine of a vehicleflows through the generator 104, as indicated by arrows 103 and 105, andthe generator absorbs heat from the exhaust gas and transfers this heatto a solution, for example water with dissolved ammonia, beingcirculated through the heat exchanger portion of the generator 104. As aresult, the solute (e.g., the ammonia) boils out of solution and isvaporized and ammonia gas progresses through valve 106, which isconfigured to direct the ammonia gas towards the condenser 108 while thesystem 100 operates in the cold storage mode. The solvent of thesolution (e.g., water) is left behind at the generator 104. As anexample, dividing line 130 illustrates the division between the portionof the system 100 where an ammonia/water solution is circulated (e.g.,through the absorber 116, the absorber pre-cooler 118, and the generator104) and the portion of the system 100 where substantially only ammoniais circulated (the valve 106, the condenser 108, the evaporatorpre-cooler 110, the orifice 112, and the evaporator 114).

Further, exemplary test results provide an approximate indication of thetemperatures and pressures that may be observed at various stages in theprocess 200 and in the system 100 when operating in a cooling mode. Forexample, typical exhaust gas from a diesel powered truck may enter thegenerator 104 at a temperature of about 400 degrees Celsius and may exitthe generator 104 at a temperature of about 300 to 380 degrees Celsius,assuming the diverter valve 102 is not diverting any of the exhaust gasthrough the bypass path 107. Pressure in the heat exchanger portion ofthe generator 104 may reach about 120 to 250 psig, resulting in ammoniagas travelling towards the condenser 108 at a pressure of about 120-250psig and a temperature of approximately 130 degrees Celsius. Whilespecific examples and/or ranges of observed temperatures and/orpressures and provided here and further on in the description, thesetemperatures and pressures are dependent on the exact design andoperating mode of the system 100 and may vary substantially depending onthe desired design criteria and operating mode of the system 100. Inother words, the examples of observed pressures and temperatures in thesystem 100 are provided as examples only and are not intended to belimiting. Further, while an ammonia/water solution is provided as anexample as a suitable solvent/solute for operating the system 100, anysuitable solvent/solute combination may be used, depending on the designcriteria of a particular application.

Next at a block 204, the ammonia arriving at the condenser 108 is cooledand condensed into a liquid to surrender some of the heat carried by theammonia gas. In a cooling mode of the system 100, it may be the pressureof the ammonia gas that is desired to act as an energy source at theevaporator 114, however the resulting high temperature assumed by theammonia is not needed and the ammonia is therefore cooled beforearriving at the evaporator 114. For example, the condenser 108 may coolthe ammonia to approximately 50 to 60 degrees Celsius by transferringthe heat to the surrounding air using a coil and fan design liquid toair heat exchanger. The ammonia may remain at 120-250 psig on exitingthe condenser 108 and travelling towards the evaporator pre-cooler 110.

Next, at a block 206, the ammonia liquid is further cooled, for examplein a first fluid passage (e.g., a fluid coil) at the evaporatorpre-cooler 110. The heat exchanger portion of the evaporator pre-cooler110 may be of the liquid to liquid type and transfers thermal energybetween the first fluid passage going from the condenser 108 to theevaporator 114 (e.g., the first coil) and from the fluid passage goingbetween the evaporator 114 and the absorber 116 (e.g., a second coil).The ammonia leaving the first coil of the evaporator pre-cooler 110 willbe cooler than the ammonia liquid entering the second coil of theevaporator pre-cooler 110. For example, the ammonia liquid leaving thefirst coil of the evaporator pre-cooler 110 may be at a temperature ofabout 50 degrees Celsius and a pressure of about 120-250 psig.

Next, at a block 208, the ammonia gas passes through the spray orifice112 and passes into or is injected into the evaporator 114. The orifice112 creates a boundary between the high pressure side of the system 100and the low pressure side of the system 100, illustrated by line 132. Asthe ammonia passes through the orifice 112 into the cavity of theevaporator 114 (e.g., through a first fluid passage of the evaporator114), the ammonia vaporizes because the ammonia encounters an area oflower pressure, which also forces the temperature of the ammonia downsignificantly. In the process of vaporizing, the ammonia absorbs thermalenergy through the heat exchanger portion of the evaporator 114 from thewater/glycol mixture being circulated through a second fluid passage(e.g., a fluid coil) of the evaporator 114, thereby cooling thewater/glycol mixture, which travels onwards to the thermal tank inputfluid passage (e.g., a coil and circuit) 122. The ammonia that entersthe evaporator 114 after passing through the orifice 112 may have atemperature of approximately −10 to −5 degrees Celsius and a pressure ofapproximately 0-5 psig. The ammonia gas that leaves the evaporator 114and travels back to the evaporator pre-cooler 110 may have, for example,a temperature between −5 and 0 degrees Celsius and a pressure ofapproximately 40 to 55 psig.

Next, at a block 210, the ammonia gas passes again through theevaporator pre-cooler 110, this time through the second fluid passageand absorbs heat surrendered by the first fluid passage at block 206.The ammonia gas may leave the second coil of the evaporator pre-cooler110 at temperature of about 10 degrees higher than on entering thesecond fluid passage of the evaporator pre-cooler 110, and the ammoniagas travels onwards through the low pressure side of the system 100towards the absorber 116. Blocks 206 and 210 of the process 200 work inconjunction with each other since blocks 206 and 210 make use of theevaporator pre-cooler 110 and are optional and aim to increaseperformance of the system 100.

Next at a block 212, the ammonia is absorbed back into the water. Thewater that the ammonia absorbs into may be the nearly ammonia free waterproduced at the block 202 when the ammonia boils out of theammonia/water solution. The ammonia gas travels through the absorber 116that includes a heat exchanger that allows the ammonia gas to dissolveback into the water by cooling both fluids to a temperature where suchcan occur. The absorber 116 may include a spray bar at its lower end,which the ammonia is fed through where the ammonia bubbles to the topand is largely absorbed in the water. The water/ammonia solution may bepumped up to a higher pressure and temperature (e.g., across line 132 bypump 128 c) and arrive next at the absorber pre-cooler 118.

Next at a block 214, the water/ammonia solution passes through theabsorber pre-cooler 118. Block 214 that uses the absorber pre-cooler 118may be an optional step in the process 200 that aims to increase theefficiency of the system 100 and the absorber pre-cooler 118 may be anoptional feature of the system 100. Hence, the block 214 and theabsorber pre-cooler 118 may not be needed for the functioning of thesystem 100. In embodiments that do use the pre-cooler 118, thewater/ammonia solution travelling towards the generator 104 through afirst fluid passage (e.g., a first coil) of the pre-cooler 118 absorbsheat while the water travelling from the generator 104 to the absorber116 (e.g., water that has had the ammonia boiled out of solution)through a second fluid passage (e.g., a second coil) of the pre-cooler118 is cooled to bring the water closer to the temperature wherere-absorption of ammonia will occur at the absorber 116. Thewater/ammonia solution arriving at the generator 104 completes the cycleof the process 200 and the process 200 returns to the block 202.

Referring now to FIGS. 3a and 3b , collectively referred to as FIG. 3,FIG. 3a shows in block diagram form a thermal auxiliary power unit orsystem 100 operating in a heat storage mode according to one aspect ofthe present description. In FIG. 3a , the path from the valve 106 to thecondenser 108 to the pre-cooler 110 to the evaporator 114 is greyed out,illustrating that this path is not used when the system 100 operates inheat storage mode. FIG. 3b shows in flow chart form the process 300 ofthe thermal auxiliary power unit or system 100 operating in a heatstorage mode according to one aspect of the present description.

At a first block 302, exhaust from an engine of a vehicle flows throughthe generator 104, as indicated by arrows 103 and 105, and the generatorabsorbs heat from the exhaust gas and transfers this heat to theammonia/water solution being circulated through the heat exchangerportion of the generator 104. As a result, the ammonia is vaporized andboils out of solution and ammonia gas flows through valve 106, which inthe present example is now configured to direct the ammonia gas directlytowards the evaporator 114 while the system 100 operates in the heatstorage mode. As an example, dividing line 130 illustrates the divisionbetween the portion of the system 100 where an ammonia/water solution iscirculated (e.g., through the absorber 116, the absorber pre-cooler 118,and the generator 104) and the portion of the system 100 wheresubstantially only ammonia is circulated (e.g., through the valve 106and the evaporator 114). Water solvent is left behind and is directedtowards the absorber pre-cooler 118. The low pressure/high pressuredividing line 132 shown in FIG. 3a should be ignored, as relativelylittle pressure differentials exist in the system 100 when operating inthe heat storage mode as opposed to when operating as an absorptioncycle.

Exemplary test results provide an approximate indication of thetemperatures and pressures that may be observed at various stages in theprocess 300 and the in the system 100. For example, typical exhaust gasfrom a diesel powered truck may enter the generator 104 at a temperatureof about 400 degrees Celsius and may exit the generator 104 at atemperature of about 300 to 380 degrees Celsius, assuming the divertervalve 102 is not diverting any of the exhaust gas through the bypasspath 107. Pressure in the heat exchanger portion of the generator 104may reach about 120-150 psig, resulting in ammonia gas travellingtowards the evaporator 114 at a pressure of about 120-150 psig and atemperature of approximately 100 degrees Celsius. While specificexamples and/or ranges of observed temperatures and/or pressures areprovided here and further on in the description, these temperatures andpressures are dependent on the design and operating mode of the system100 and may vary depending on the particular design criteria andoperating mode of the system 100. In other words, the examples ofobserved pressures and temperatures in the system 100 are provided asexamples only and are not intended to be limiting.

Next, at a block 304, the ammonia gas passes into a first fluid passage(e.g., a first coil) of a heat exchanger, for example in the evaporator114, where the gas surrenders thermal energy and cools. In the processof cooling, the ammonia surrenders thermal energy through the heatexchanger portion of the evaporator 114 to the water/glycol mixturebeing circulated through a second fluid passage (e.g., a second coil) ofthe evaporator 114, thereby heating the water/glycol mixture, whichtravels onwards to the thermal tank input coil and circuit 122. Theammonia that enters the evaporator 114 may have a temperature ofapproximately 100 degrees Celsius and a pressure of approximately120-250 psig.

Next, at a block 306, the ammonia gas passes through the evaporatorpre-cooler 110. In a heat storage mode the flow of ammonia may bypassnot only the orifice 112 on its way to the evaporator 114 but also thepre-cooler 110 so almost no heat transfer occurs at this point. In theprocess 300, the evaporator pre-cooler 110 may be used as a liquid toair heat exchanger, simply providing the function of cooling the ammoniagas to expel excess heat. The ammonia may leave the evaporatorpre-cooler 110 at a temperature of about 10 degrees lower than uponentering the evaporator pre-cooler 110, and the ammonia gas travelsonwards through the system 100 towards the absorber 116. The block 306of the process 300 is optional, as is the direction of the ammoniathrough the evaporator pre-cooler shown in FIG. 4. Alternatively, theammonia may proceed directly from the evaporator 114 to the absorber 116when the system 100 operates in a heat storage mode.

Next at a block 308, the ammonia is absorbed back into the water of theammonia/water solution. The water that the ammonia absorbs into may bethe nearly ammonia free water produced at the block 302 when the ammoniais vaporized from the ammonia/water solution. The ammonia gas travelsthrough the absorber 116 that includes a heat exchanger that allows theammonia gas to dissolve back into the water by cooling both fluids(e.g., the ammonia and the water) to a suitable temperature where suchcan occur. The absorber 116 may include a spray bar at its lower end,which the ammonia is fed through where the ammonia bubbles through thewater to the top and is largely absorbed in the water.

Next at a block 310, the water/ammonia solution passes through theabsorber pre-cooler 118. Block 310 that uses the absorber pre-cooler 118may be an optional step in the process 300 that aims to increase theefficiency of the system 100 and the absorber pre-cooler 118 may be anoptional feature of the system 100. Hence, the block 310 and theabsorber pre-cooler 118 may not be needed for the functioning of thesystem 100. In embodiments that do use the pre-cooler 118, thewater/ammonia solution travelling towards the generator 104 through afirst fluid passage (e.g., a first coil) of the pre-cooler 118 absorbsheat while the water travelling from the generator 104 to the absorber116 (e.g., water that has had the ammonia vaporized out of solution)passes through a second fluid passage (e.g., a second coil) of thepre-cooler 118 is cooled to bring the water closer to the temperaturewhere re-absorption of ammonia is best achieved at the absorber 116. Thewater/ammonia solution arriving at the generator 104 completes the cycleof the process 300 and the process 300 returns to the block 302.

Reference is next made to FIG. 4, which illustrates in flow chart form aprocess 400 executed by the controller 128 in controlling the system100. In one example, the controller 128 may be implemented as anelectronic control module (ECU) designed to facilitate the desiredoperation of the system 100, also referred to as a Hybrid AuxiliaryPower Unit (HAPU), by monitoring and controlling various aspects of thesystem 100 to achieve the function of providing heating and/or coolingto a vehicle and capturing and reusing what would otherwise be lostenergy expelled as heat in the exhaust of the vehicle in an effort toreducing the overall carbon footprint of the vehicle. The controller 128may be integral to the system 100 and may enable the system 100 tofunction according to the design criteria of the intended application.As shown in a first block 402, the controller may monitor and/or collectdata pertaining to operating parameters of the system 100 and/or thevehicle on which the system 100 is installed including but not limitedto pressure, temperature, voltage, liquid level, flow, and/or vehicleoperator inputs. Using data collected from these inputs and processingthe information using control logic, the controller 128 directs theactions of the components of the system 100 to maintain properfunctioning of the system 100. The components of the system 100 that areeither monitored or controlled by the controller 128 include but are notlimited to valves, fans, actuators, relays, contactors, chargecontrollers, pumps and/or outputs. One possible use of the outputs maybeto illustrate aspects of the system operation to the user.

In one example, the controller 128 monitors aspects of the system 100operation and allows the thermal cycle (e.g., illustrated in connectionwith FIGS. 2 and 3) and electrical system to function in harmony toprovide conditioned air to the cab of the vehicle such as a truck. Thecontroller 128 may be responsible for controlling several primaryfunctions of the system 100, as described below. Generally, as indicatedby block 403, the controller 128 controls a number of components of thesystem 100 coupled to outputs of the controller 128 to provide forproper functioning of the system 100.

The controller 128 may be electrically coupled to the exhaust divertervalve 102, which may be a 3-way 2-position valve configured by thecontroller 128 to ensure that the thermal energy delivered to thegenerator 104 from the exhaust is appropriate for the system 100 anddivert the exhaust away from the generator 104 if the system 100 becomestoo hot or is in danger of becoming too hot. As illustrated in block404, the controller 128 controls the position of the exhaust divertervalve 102 according to relevant inputs received from, for example,transducers in the system 100. In one example, the valve 102 maycompletely divert the exhaust to or away from the generator 104 or blendthe exhaust flow between the generator 104 and bypass path 107 toachieve the suitable heat delivery to the generator 104. In one example,the controller 128 monitors electrical signals from transducersindicating temperatures and/or pressures at various locations in thesystem 100 and generates a decision based on these signals according tocontrol logic stored in the controller 128 and decides whether toincrease or decrease the amount of thermal energy delivered to thegenerator 104 by comparing the signals the controller 128 receives fromone or more of the input transducers against specific targets programmedinto the control logic. The controller generates an output signal forthe diverter valve 102 accordingly and operates the diverter valve 102accordingly. If the controller 128 detects a fault based on one or moreof the input signals, the controller 128 may generate an output signalto close the diverter valve 102 forcing all the thermal energy away fromthe generator 104 and through the bypass path 107 as part of a safetyshutdown sequence.

The controller 128 may further be electrically coupled to valve 106,which may be a 3-way 2-position valve responsible for providing thesystem 100 with the ability to switch between a heating and coolingmode. As illustrated at block 406, the controller 128 controls theposition of the valve 106 thereby selecting the operating mode of thesystem 100 based on relevant inputs. When cooling is desired, the valve106 directs the flow of ammonia through the condenser 108 and the system100 functions as an absorption cycle, as described above in connectionwith FIG. 2. If heating is desired, the valve 106 directs the flow ofammonia through a secondary circuit bypassing the condenser 108 andspray orifice 112, which eliminates the cooling portion of the system100 and sends hot ammonia to the evaporator 114, as described above inconnection with FIG. 3. In one example, the controller 128 generates adecision as to which mode is appropriate, for example by receivingsignals generated by manual inputs coupled to inputs of the controller128 such as a button actuated by a user. In another example, thecontroller 128 generates a decision as to which mode is appropriate byautomatically sensing the temperature, for example by receiving signalsfrom an electrical temperature transducer coupled to an input of thecontroller 128 that may reside in the cab and/or outside of the vehicle.The controller 128 may read a signal generated by the temperaturetransducer coupled to an input and anticipate the proper action tomaintain user comfort based on control logic stored in the controller128 and the controller 128 may generate an output signal for the valve106 causing the valve 106 to move to the desired position to place thesystem 100 in either cold storage mode or heat storage mode.

The controller 128 may further be electrically coupled to any of thepumps (for example, pumps 128 a, 128 b, and/or 128 c) shown in FIG. 1.For example, the controller 128 may be electrically coupled to the pump128 c, which may be an ammonia/water solution pump responsible forcreating the return flow of the water/ammonia solution from the absorber116 to the generator 104 in the final stages of the processes 200 or 300described in connection with FIGS. 2 and 3. As indicated at block 408,the controller 128 controls the pumps used to maintain the functioningof the system 100. In one example, the controller 128 may controlwhether the pumps are on or off and at what speed the pumps areoperating. In one example, the controller 128 controls operation of thepump, for example by generating an appropriate output signal to controla relay coupled to the pump 128 c, to maintain the suitable liquid levelin both pressure vessels (e.g., the absorber 116 and the generator 104)by gathering information from a variety of sensors or transducers thatprovide signals indicating, for example, fluid flow at various stages ofthe system 100, temperature in various sections of the system 100,pressure at various sections of the system 100, and/or liquid levelindicators at various sections of the system 100. The controller 128 mayuse one or more of these inputs to compare the readings the controller128 obtains from the sensors or transducers against specific targetsprogrammed in the control logic of the controller 128 and generate anappropriate output signal to control the pump 128 c to satisfy theoutput conditions dictated by the control logic.

The controller 128 may further be electrically coupled to the pump 128 aand/or the pump 128 b, which may be responsible for circulating thesolution (e.g., water/glycol) between two or more heat exchangers inorder to transfer thermal energy from one component to the next in thesystem 100. In one example, the controller 128 monitors the signalsindicating temperatures supplied by temperature transducers coupled toheat exchangers (e.g., the evaporator 114 and/or the thermal storagetank fluid passages 122, 124) and determines through program logicstored in the controller 128 if the transfer of thermal energy isappropriate in order to meet the end thermal objectives of the system100 by comparing the temperatures indicated by the temperaturetransducers against targets stored in the code. The controller 128 thenoperates the pumps accordingly.

The controller 128 may further be electrically coupled to a number ofcooling fans (not shown). Any of the components of the system 100incorporating a heat exchanger may optionally include a cooling fan, forexample the condenser 108. A fan that blows air through the condenser108 may be responsible for allowing such a liquid to air heat exchangerto function more efficiently and to reject the proper heat load tosurrounding environment cooling the fluid media within (e.g., theammonia, in the case of the condenser 108). As indicated by block 410,the controller 128 controls any cooling fans installed in the system 100based on the relevant input signals received by the controller 128. Inone example, the controller 128 may control operation of the fan tomaintain the desired cooling effect on the heat exchanger, such as thecondenser 108, by monitoring input signals generated by temperaturetransducers and comparing these inputs to targets encoded in the controllogic of the controller 128. Fan operation may be adjusted accordingly.For example, the fan may either be turned completely on or off and, whenon, the speed of the fan may be set accordingly. In one example, a fancoupled to the condenser 108 may operate when the system 100 is in coldstorage mode, but not when the system 100 is in heat storage mode sincethe condenser 108 is not used in heat storage mode. Further, in oneexample, the speed of the fan may be suitably controlled by thecontroller 128 to achieve the desired cooling rate of fluid passingthrough the heat exchanger.

The controller 128 may further be coupled to valve 130 that controls theflow of solution flowing through the thermal tank output fluid passage124. As indicated by block 412, the controller 128 controls the positionof the valve 130 based on relevant inputs, which controls use of theenergy stored in the thermal storage tank 122. The valve 130 may be a3-way 3-position dual circuit type and may direct the flow of thesolution (e.g., glycol/water) between the vehicle's HVAC 126, thevehicle's engine, and thermal storage tank 120. In one example, thecontroller 128 decides which flow path is appropriate by receiving inputsignals, for example generated by manual inputs of a user using abutton, which indicates the desired operating mode of the system 100.The controller may further receive inputs from temperature transducersindicating the temperatures in any of the previously mentionedcomponents and the controller 128 may then decide the most appropriateaction to achieve the goal of the system 100 and send the appropriateoutput signal to the valve 130. As previously discussed in the exemplarycontext of the system 100 operating in heat storage mode, the valve 130may have three possible positions. The valve 130 may be closed, forexample when the vehicle is moving and the heat source from the thermalstorage tank is currently not needed while the system 100 is heating thesolution in the thermal storage tank 120 to store thermal energy forlater use and therefore restoring conventional heating input from theengine to the HVAC 126. Second, the valve may be in a first openposition allowing the solution to pass to the HVAC unit 126, therebyallowing the HVAC 126 to use the stored heat such as when the vehicle isparked with the engine off and a user of the system 100 desires thecabin of the vehicle to be heated. Third, the valve may be in a secondopen position directing the flow of solution to the vehicle engine. Thismay be useful during a cold start of the engine during cold conditions,allowing the user of the system 100 to pre-heat the engine beforestarting the engine, thereby reducing emissions emitted by the engineduring a cold start and allowing the user to immediately use the vehicleheating system once the engine is started.

The controller 128 may further be coupled to one or more chargecontrollers providing an electrical charge control function. The chargecontroller is responsible for but not limited to regulating the flow ofelectricity in and out of the batteries of the system 100 (not shown)contained within a number of optional components of the system 100, suchas an energy storage system, a plug-in battery charger, a photovoltaicarray, and/or the bus of the vehicle or vehicle components. In oneexample, the controller 128 monitors the voltage coming in and out ofthe system 100 and regulates the flow of electricity while taking intoaccount many different parameters for example, time of day, batterystate of charge (SOC), vehicle operation, and the amount of poweravailable to capture. The controller 128 receives signals indicatingsome or all of this information and decides a course of action for thecharge controller based on the program logic programmed into thecontroller 128. As indicated at block 414, the controller 128 controlsone or more charge controllers (not shown) based on relevant inputs.

While the process or method 400 is shown as occurring in a particularorder, any of the blocks 402, 404, 406, 408, 410, 412, and 414 may berearranged as the order of the blocks is not critical to the functioningof the system 100. Further, it will be understood by those skilled inthe relevant arts that the method 400 when executed by the controller128 is cyclical and/or iterative, and the controller 128 typicallyexecutes the process 400 several times per second. Further, thefunctions illustrated by the blocks 402, 404, 406, 408, 410, 412, and414 are intended to be exemplary and one or more of the blocks may beoptional, depending on the design criteria of a particular application.Further yet, the method 400 is intended to illustrate some of the majorcontrol aspects of the system 100. It will be understood by thoseskilled in the relevant arts that the controller 128 performs morefunctions than what is illustrated by the method 400.

Reference is next made to FIG. 5, which shows a bottom view and acorresponding sectional view of the generator 104 for use with a thermalauxiliary power unit according to one aspect of the present description.FIG. 5 illustrates one example of the generator 104 that may be suitablefor use with the system 100 and is not intended to be limiting. Anygenerator may be used according to the design criteria of a particularapplication. The generator 104 generally comprises an outer tube orshell 502, end plates 504, 506, an inner tube 508, an exhaust gaspassage 509, annular rings 510, a separation ring 512, a separation zone514, and an ammonia exit line 516.

The outer shell 502 portion of the generator 104 contains thepressurized and heated fluid, for example the ammonia and watersolution. In one example, the solution may have a concentration thatvaries from a few percent of ammonia by weight to as high as 20% ammoniaby weight. In one example, the generator 104 is designed as a pressurevessel to appropriate codes in the jurisdiction where the generator isused. Internal pressure of the generator 104 may rise to 250 psig whileoperating from 50 psig in a quiescent state. The temperature range ofthe generator may vary from −40 degrees Celsius while inoperative to 130degrees Celsius or more internally during normal operation. During anoverheat condition, the outer shell 502 may reach up to 250 degreesCelsius. The pressure vessel boundary includes the outer tube 502 asshown in FIG. 5 and two endplates 504, 506 which are formed such thatthe end plates 504, 506 act as closures between the outer tube 502 andthe concentric inner tube 508. The outer shell 502 may be fabricatedfrom carbon steel such as seamless tubing, having properties appropriatefor the conditions and composition of the contained fluids such as, butnot limited to, ASTM A516, and in some applications a grade of stainlesssteel such as SS304 may be used.

The inner tube 508 may form part of the exhaust gas passage 509 from theengine to the atmosphere. The function of the inner tube may be toprovide a passage for the hot exhaust gases that provide the energyharvested by the system 100 and also withstand on the outside of theinner tube 508 the high pressures generated by the pressurised workingfluid (e.g., the solution) in the absorption circuit. The inner tube 508may conduct heat from the flowing exhaust gases into the solution withthe aid of the annular rings 510, described below. In one example, theinner tube 508 may be manufactured from carbon steel such as seamlesstubing and may have properties appropriate for the conditions andcomposition of the contained fluids such as, but not limited to, ASTMA516, and in some applications a grade of stainless steel such as SS304may be used.

These annular rings 510 surround the inner tube 508 and serve toincrease the amount of heat conducted from the hot exhaust gas flowingthrough the inner tube 508 into the solution flowing through the outertube 502 by increasing the amount of surface area available for heattransfer and helping to raise the temperature and pressure of thesolution therefore increasing the effectiveness of the generator 104 andits ability to better vaporize the solute from the solution. In oneexample, the rings 510 have a tight fit to the inner tube 508, but havea radial clearance relative to the outer tube 502 enabling fractionationof the solution while stabilizing the fluid column against violentbubbling and sloshing as the vehicle moves. The rings 510 may befabricated of a material compatible with the inner tube 508 and theouter tube 502. In one example, all the metallic components of thegenerator 104 may be made from the same materials for ease offabrication.

The separation ring 512 works to separate the lower space (e.g., to theleft of the separation ring 512 as shown in FIG. 5) which is a fluidheating and boiling zone whereby a wet gas (e.g., ammonia) with someentrained water from the separation zone is driven from the solution(e.g., water and ammonia) and an upper space (e.g., to the right of theseparation ring 512 as shown in FIG. 5) where fluid droplets are largelyremoved leaving a mostly dry gas (e.g., ammonia) to leave the vessel. Inone example, the ring 512 may have a tight fit with both the inner tube508 and the outer tube 502 and may be welded to the inner tube 508 forease of assembly. The ring 512 may be fabricated from materialscompatible with the tubes 502 and 508 as previously described. The ring512 may include an annular plate penetrated by a series of holes whichmay be, in one example, approximately 25% in diameter of the annulargap. The open area of the plate created by the holes may be, but is notlimited to, 10 to 20% of the total annular area.

The separation zone 514 includes a volume. In one example, the volumemay be packed with a droplet coalescence material such as stainlesssteel wool or other like material which provides a very high surfacearea. Droplets of solute (e.g., liquid water) form on these surfaces anddrain back to the liquid space below the separation ring 512. The gas(e.g., vaporized ammonia) that exits the vessel through the ammonia exitline 516 at the top is nearly all ammonia gas (e.g., as much as 99%ammonia gas with very little water vapour, for example 1% water vapour).

The embodiments of the present disclosure described above are intendedto be examples only. Those of skill in the art may effect alterations,modifications and variations to the particular embodiments withoutdeparting from the intended scope of the present disclosure. Inparticular, selected features from one or more of the above-describedembodiments may be combined to create alternative embodiments notexplicitly described, features suitable for such combinations beingreadily apparent to persons skilled in the art. The subject matterdescribed herein in the recited claims intends to cover and embrace allsuitable changes in technology.

The invention claimed is:
 1. A controller for a heat capture and storagesystem configured to capture and store energy from heat expelled inengine exhaust, the controller comprising a plurality of inputs, aplurality of outputs, and at least one processor coupled to a memory forstoring within the memory instructions executable by the at least oneprocessor, the controller configured by execution of the instructionsstored in the memory to: receive signals at one or more of the pluralityof inputs, the signals representing at least one operating parameter ofthe heat capture and storage system; and based on at least one operatingparameter, generate signals at one or more of the plurality of outputsfor controlling at least one component of the heat capture and storagesystem to capture and store the energy from the heat expelled in theengine exhaust; wherein the controller is coupled, by way of at leastone of the signals at one or more of the plurality of outputs, to one ormore pumps configured to circulate a solution carrying thermal energythrough the heat capture and storage system, and the controller isconfigured to control a speed of the one or more pumps.
 2. Thecontroller of claim 1, wherein the controller is coupled, by way of atleast one of the signals at one or more of the plurality of outputs, toan operating mode control valve included in the heat capture and storagesystem, and the controller is configured to switch the heat capture andstorage system between a heat storage mode and a cold storage mode bycontrolling a flow path through the operating mode control valve.
 3. Thecontroller of claim 2, wherein the signals received at the one or moreof the plurality of inputs include a signal indicating a temperature,and the controller is configured to switch the heat capture and storagesystem between the heat storage mode and the cold storage mode inresponse to that signal.
 4. The controller of claim 1, wherein the atleast one component controlled by the controller comprises at least oneof an exhaust diverter valve, an operating mode control valve, a fluidpump, a cooling fan, or a charge controller.
 5. The controller of claim1, wherein the controller is coupled, by way of at least one of thesignals at one or more of the plurality of outputs, to an exhaustdiverter valve included in the heat capture and storage system, and thecontroller is configured to control the exhaust diverter valve to divertat least a part of the engine exhaust away from a generator of the heatcapture and storage system.
 6. The controller of claim 5, wherein thesignals received at the one or more of the plurality of inputs include asignal indicating at least one of a temperature and a pressure in theheat capture and storage system, and the controller is configured tocontrol the exhaust diverter valve in response to that signal.
 7. Thecontroller of claim 5, wherein the controller is configured to detect afault condition of the heat capture and storage system based on thesignal indicating at least one of a temperature and a pressure in theheat capture and storage system.
 8. The controller of claim 7, whereinthe controller is configured to control the exhaust diverter valve todivert substantially all the engine exhaust away from the generator inresponse to detecting the fault condition.
 9. The controller of claim 1,wherein the signals received at the one or more of the plurality ofinputs include a signal indicating a temperature, and the controller isconfigured to control the speed of the pump to meet a specifiedtemperature.
 10. The controller of claim 1, wherein the signals receivedat the one or more of the plurality of inputs include a signalindicating a pressure, and the controller is configured to control thespeed of the one or more pumps to meet a specified pressure.
 11. Thecontroller of claim 1, wherein the signals received at the one or moreof the plurality of inputs include a signal indicating a liquid level inthe heat capture and storage system, and the controller is configured tocontrol the speed of the pump to meet a specified liquid level.
 12. Thecontroller of claim 1, wherein the controller is coupled, by way of atleast one of the signals at one or more of the plurality of outputs, toa fan included in the heat capture and storage system, and thecontroller is configured to control a speed of the fan to control acooling rate of solution carrying thermal energy in the heat capture andstorage system.
 13. The controller of claim 12, wherein the signalsreceived at the one or more of the plurality of inputs include a signalindicating a temperature, and the controller is configured to controlthe speed of the fan to meet a specified temperature.
 14. The controllerof claim 12, wherein the signals received at the one or more of theplurality of inputs include a signal indicating a pressure, and thecontroller is configured to control the speed of the fan to meet aspecified pressure.
 15. The controller of claim 1, wherein thecontroller is coupled, by way of at least one of the signals at one ormore of the plurality of outputs, to a first pump configured tocirculate a first solution through a first heat exchanger to extractthermal energy from said engine exhaust and the controller is configuredto control the first pump.
 16. The controller of claim 15, wherein thecontroller is coupled, by way of at least one of the signals at one ormore of the plurality of outputs, to a second pump configured tocirculate a second solution through a second heat exchanger to transferthermal energy from to the second solution, and the controller isconfigured to control the second pump.
 17. The method of claim 16,wherein the control signals include a signal for controlling a secondpump configured to circulate a second solution through a second heatexchanger to transfer thermal energy from to the second solution, andthe controller is configured to control the second pump.
 18. Aprocessor-implemented method of controlling a heat capture and storagesystem configured to capture and store energy from heat expelled inengine exhaust, the method comprising: receive, at at least oneprocessor, operating signals representing at least one operatingparameter of the heat capture and storage system; and generating, at theat least one processor, control signals for controlling at least onecomponent of the heat capture and storage system based on the at leastoperating parameter, wherein the control signals include a signal forcontrolling a pump configured to circulate a solution carrying thermalenergy through the heat capture and storage system.
 19. The method ofclaim 18, wherein the control signals include a signal for controllingan operating mode control valve included in the heat capture and storagesystem to cause the heat capture and storage system to switch between aheat storage mode and a cold storage mode.
 20. The method of claim 18,wherein the control signals include a signal for controlling an exhaustdiverter valve included in the heat capture and storage system to divertat least a part of the engine exhaust away from a generator of the heatcapture and storage system.
 21. The method of claim 18, whereincontrolling the pump includes controlling a speed of the pump to meet aspecified temperature.
 22. The method of claim 18, wherein controllingthe pump includes controlling a speed of the pump to meet a specifiedpressure.
 23. The method of claim 18, wherein controlling the pumpincludes controlling a speed of the pump to meet a specified liquidlevel in the heat capture and storage system.
 24. The method of claim18, wherein the control signals include a signal for controlling a fanincluded in the heat capture and storage system to control a coolingrate of solution carrying thermal energy in the heat capture and storagesystem.
 25. The method of claim 18, wherein the control signals includea signal for controlling a first pump configured to circulate a firstsolution through a first heat exchanger to extract thermal energy fromsaid engine exhaust.